What effect does a very small primary clearance angle have on the cutting action of a milling cutter?

A very small primary clearance angle can significantly impact the cutting action of a milling cutter. When the primary clearance angle is too small, it means that there isn't enough relief space between the cutting edge and the workpiece. This leads to the back of the cutting edge, or the land, rubbing against the material being machined rather than cutting through it effectively.

As a result, the cutter does not engage the material optimally, leading to increased friction and heat at the cutting edge. This rubbing action causes poor cutting performance, which can affect the overall efficiency of the milling process and result in undesired outcomes, such as an increased wear rate on the tool and potential issues with the finish of the workpiece.

Moreover, the inability of the cutter to effectively penetrate the material can create additional challenges, including an inconsistent surface finish and reduced tool life. Thus, recognizing the importance of the primary clearance angle is crucial for achieving desirable results in milling operations.